DLMF For nearly 50 years, a stan­dard ref­er­ence in math­e­mat­i­cal work has been Abramowitz and Stegun’s (1964) Hand­book of Math­e­mat­i­cal Func­tions with For­mu­las, Graphs, and Math­e­mat­i­cal Tables. It has pro­vided a mar­vel­lous col­lec­tion of results and tables that have been indis­pens­able for a gen­er­a­tion of math­e­mati­cians. I’ve used it to look up com­pu­ta­tion­ally effi­cient meth­ods for cal­cu­lat­ing Bessel func­tions or gamma func­tions, or to find one of those trigono­met­ric iden­ti­ties I learned in high school and no longer remem­ber. Appar­ently nearly 1 mil­lion copies of the hand­book have been printed and it has also been scanned and put online. Lately, the hand­book has fallen out of favour a lit­tle, partly because there is not such a need for it. We no longer need tables for trigono­met­ric func­tions or log­a­rithms, and a lot of func­tions are built into R, includ­ing Bessel func­tions and vari­a­tions on the gamma func­tion. Another rea­son for its declin­ing pop­u­lar­ity has been the rise of online resources: if you want to know some­thing about orthog­o­nal poly­no­mi­als, there is a good chance it is cov­ered in the Wikipedia arti­cle. Now the hand­book has been reis­sued as the NIST Hand­book of Math­e­mat­i­cal Func­tions (Cam­bridge Uni­ver­sity Press) with a free web edi­tion called the NIST Dig­i­tal Library of Math­e­mat­i­cal Func­tions (DLMF).

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